Method and arrangement in a hybrid vehicle

Abstract

In a method and an arrangement for powering up a DC distribution system in a hybrid vehicle power train, the power train includes an electric storage system, an internal combustion engine, an electric motor/generator, a clutch device to connect the electric motor/generator to the internal combustion engine, a power electronics unit with a voltage regulator connected to the electric motor/generator, and an electronic control unit for controlling the power train. The electric storage system and the electric motor/generator are connectable to one or more electrical loads for driving the vehicle. The powering up includes initializing internal combustion engine ignition, initializing a diagnostics test of power train components, cranking the internal combustion engine, requesting pre-charge of the electrical loads from the power electronics unit, connecting the electric storage system to the electrical loads when the pre-charge and the diagnostics test are completed, and resuming normal operation for the power electronics unit.

The invention claimed is: 
     
       1. A method for powering up a DC distribution system in a hybrid vehicle power train, the power train comprising an electric storage system, an internal combustion engine, an electric motor/generator, a clutch device to connect the electric motor/generator to the internal combustion engine, a power electronics unit with a voltage regulator connected to the electric motor/generator, and an electronic control unit for controlling the power train, wherein the electric storage system and the electric motor/generator are connectable to one or more electrical loads for driving, the vehicle, comprising
 initializing internal combustion engine ignition; 
 initializing a diagnostics test of power train components; 
 cranking the internal combustion engine using a starter motor; 
 requesting pre-charge of the electrical loads from the power electronics unit, comprising requesting a predetermined voltage from the power electronics unit and controlling the voltage regulator to enter a pre-charge mode to power up the DC distribution system; 
 connecting the electric storage system to the electrical loads when the diagnostics test and the pre-charge are completed; and 
 resuming normal operation for the power electronics unit to complete powering up of the DC distribution system. 
 
     
     
       2. A method according to  claim 1 , comprising, requesting pre-charge from the power electronics unit, which enters a pre-charge mode and requests a predetermined voltage from the voltage regulator. 
     
     
       3. A method according to  claim 2 , comprising requesting a set predetermined voltage from the voltage regulator, which voltage corresponds to a voltage supplied to vehicle one or more electric power takeoff units in case of electric storage system failure. 
     
     
       4. A method according to  claim 2 , comprising the predetermined voltage being lower than the electric storage system voltage. 
     
     
       5. A method according to  claim 1 , comprising controlling the voltage generated by the electric motor/generator using the voltage regulator to supply a predetermined pre-charge voltage. 
     
     
       6. A method according to  claim 1 , comprising connecting the voltage generated by the electric motor/generator using the voltage regulator to supply a voltage gradually increasing towards a predetermined pre-charge voltage. 
     
     
       7. A method according to  claim 1 , comprising connecting electric storage system to the electrical loads when a diagnostics test for the electric, storage system is completed. 
     
     
       8. A method according to  claim 1 , comprising preventing connection of the electric storage system to the electrical loads if the diagnostics test indicate an electric storage system failure. 
     
     
       9. A method according to  claim 1 , comprising actuating the clutch device connecting the electric motor/generator to the internal combustion engine when a predetermined minimum engine speed is reached. 
     
     
       10. Arrangement for powering up a DC distribution system in a hybrid vehicle power train, the power train comprising an electric storage system, an internal combustion engine, an electric motor/generator, a clutch device to connect the electric motor/generator to the internal combustion engine, a power electronics unit with a voltage regulator connected to the electric motor/generator, and an electronic control unit for controlling the power train, wherein the electric storage system and the electric motor/generator are connectable to one or more electrical loads for driving the vehicle, wherein
 the electronic control unit is configured to initialize internal combustion engine ignition, in order to crank the internal combustion engine, to initialize a diagnostics test of power train components prior to cranking, and to request pre-charge of the electrical loads from the power electronics unit subsequent to cranking; 
 the power electronics unit is configured to pre-charge the electrical loads by means of electrical power generated by the electric motor/generator; 
 the electric storage system is configured to be connected to the electrical loads when the diagnostics test and the pre-charge are completed; and 
 the power electronics unit is configured to resume normal operation when the electric storage system is connected and powering up of the DC distribution system is completed. 
 
     
     
       11. Arrangement according to  claim 10 , wherein pre-charge is requested by the power electronics unit, which unit is configured to enter a pre-charge mode and to request a predetermined voltage from the voltage regulator. 
     
     
       12. Arrangement according to  claim 11 , wherein the voltage is requested from the voltage regulator, which voltage corresponds to a voltage supplied to one or more electric power take-off units on the vehicle in case of electric storage system failure. 
     
     
       13. Arrangement according, to  claim 11 , wherein the predetermined voltage is lower than the electric storage system voltage. 
     
     
       14. Arrangement according to  claim 10 , wherein the electric storage system is configured to be connected to the electrical loads when a diagnostics test for the electric storage system is completed. 
     
     
       15. Vehicle comprising an arrangement for powering up a DC distribution system in a hybrid vehicle power train, the power train comprising an electric storage system, an internal combustion engine, an electric motor/generator, a clutch device to connect the electric motor/generator to the internal combustion engine, a power electronics unit with a voltage regulator connected to the electric motor/generator, and an electronic control unit for controlling the power train, wherein the electric storage system and the electric motor/generator are connectable to one or more electrical loads for driving the vehicle, wherein
 the electronic control unit is configured to initialize internal combustion engine ignition, in order to crank the internal combustion engine, to initialize a diagnostics test of power train components prior to cranking, and to request pre-charge of the electrical loads from the power electronics unit subsequent to cranking; 
 the power electronics unit is configured to pre-charge the electrical loads by means of electrical power generated by the electric motor/generator; 
 the electric storage system is configured to be connected to the electrical loads when the diagnostics test and the pre-charge are completed; and 
 the power electronics unit is configured to resume normal operation when the electric storage system is connected and powering up of the DC distribution system is complete.